Because of globalization, the dependence upon foreign trade has gradually become closer, and the outbreak of Covid 19 seriously disrupts the global economy. There were significant changes in the semiconductor industry during the past two years, with the constrained capacity due to the lockdown in countries and shutdown of semiconductor companies. Many investors are concerned about how will semiconductor companies adjust to accommodate the long-term struggle. The pandemic has turned the end market of electronic products into having lower purchasing power, which will significantly impact Taiwan’s semiconductor industry. The earliest COVID-19 virus strain has been replaced by multiple mutation variants. First, the Delta variant that has dominated the world since July 2021 and the following variant became worldwide is the Omicron variant in the end of 2021. Although these variants of COVID 19 may be less deadly, it still causes fears and panic in society.
This study takes the outbreak of COVID-19 and its variants as events and selects 189 companies from the Taiwan semiconductor industry as research samples to conduct an event study, which aims to see if the pandemic brought abnormal returns to the semiconductor industry in Taiwan. The events are as follows, the first coronavirus detected in Taiwan, the unclear transmission link might lead to the community transmission in Taiwan, the outbreak of the community transmission, the Delta virus exploded in north Taiwan communities, the detection of the first Omicron virus in Taiwan.

CHAPTER 1: INTRODUCTION P.4
1.1 Research Background and Motivation P.4
1.2 Research Purpose P.5
1.3 Research Process P.7
Chapter 2 EVENTS TIMELINE RESEARCH P.8
2.1 Outbreak of COVID-19 and Introduction of its Variants P.8
2.2 Introduction of Semiconductor Industry P.9
Chapter 3 LITERATURE REVIEW P.10
3.1 Expectation Theory P.10
3.2 Efficient Market Hypothesis P.10
3.3 Signalling Theory P.11
3.4 Contagion Theory P.12
Chapter 4 RESEARCH METHODOLOGY P.13
4.1 Research Structure P.13
4.2 Research Hypothesis P.14
4.3 Sample Selection P.20
4.4 Method of the Event Study P.20
4.4.1 Process of the Event Study P.20
4.4.2 Event Date Confirmation P.21
4.4.3 Estimation of the abnormal returns P.22
4.4.4 Review the Abnormal Rate of Return P.23
Chapter 5 EMPIRICAL RESULTS P.26
5.1 P.26
5.2 P.29
5.3 P.32
5.4 P.35
5.5 P.38
Chapter 6 CONCLUSION P.41
REFERENCE P.42

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